<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="../css/reset.css">
    <style>
        nav {
            width: 600px;
            display: flex;
            line-height: 30px;
            text-align: center;
            margin: 0 auto;
        }

        nav li {
            flex: 1;
            border: 1px solid #333;
        }

        /* nav li+li {
            border-left: 0;
        } */
        nav li:not(:first-child) {
            border-left: 0;
        }
    </style>
</head>

<body>
    <nav>
        <li>01</li>
        <li>02</li>
        <li>03</li>
        <li>04</li>
        <li>05</li>
        <li>06</li>
    </nav>
</body>

</html>